Apron conveyor

ABSTRACT

A conveyor having a plurality of juxtaposed apron pans pivotally interconnected by piano hinges which facilitate independent replacement of individual apron pans.

United States Patent [151 3,690,445

Ouska 51 Sept. 12, 1972 .APRON CONVEYOR Primary Examiner-Edward A. Sroka72 Inventor: Ralph c. Ouska, l-linsdale, m. '"Y Anderson and PP [73]Assignee: FMC Corporation, San Jose,

57 ABSTRACT [22] Med: May 1971 A conveyor having a plurality ofjuxtaposed apron [2]] Appl. No.: 144,508 pans pivotally interconnectedby piano hinges which facilitate independent replacement of individualapron [52] US. Cl ..198/196 pans [51] Int. Cl ..B65g 15/30 [58] Field ofSearch ..l98/l95, 196, 189

[56] References Cited 18 Claims, 4 Drawing Figures UNITED STATES PATENTS8/1960 Rivers ..l98/l96 PAIENTEDsEPmmn 3590.445

sum 1 [1F 3 PATENTED I972 3. 690 .445

sum 2 or 3 PATENTED SEP 12 I972 SHEET 3 [IF 3 APRON CONVEYOR The presentinvention is directed to apron pan conveyors.

Apron pan conveyors consist of a plurality of juxtaposed pansarticulated with respect to each other to permit conveyor travel .alongan endless path. The material to be conveyed is carried by the apronpanswhich may themselves be and/or may require that other elements of theconveyor be of heavy and/or bulky construction to impart sufficientrigidity to the conveyor in its transverse direction. Of course, theheavier the conveyor, the greater are the drive power requirements andmore massive is the. conveyor supporting structure. On the other hand,an increase in the bulk of the. conveyor generally involves a reductionin its load-carrying capacity and, frequently, complicates thereplacement of apron pans which have worn or have been damaged, as bybending, tearing, or where heater conditions are involved, warping orburning. Wlthknownapron pan conveyors, pan replacement is an already.difficult, time-consuming and expensive task, usually involvingextensive disassembly of the conveyor. Accordingly, a primary object ofthis invention is to providea new or generally improved and moresatisfactory apron pan conveyor.

Another object of this invention is the provision of an apron panconveyor in which the pans are interconnected by piano hinges whichfacilitate replacement of individual apron pans with a minimum ofconveyor disassembly and without loss of conveyor integrity.

, Still .another object of this invention is to provide a conveyorhaving a belt of apron panswhich arearticulated to each other by pianohinges which are compact, snug and rapidly and easily disassembled.

A further object of this invention is to provide apron pan conveyorswhich are of lighter weight than known apron pan conveyors ofcorresponding width, yet which possess desired rigidity in theirtransverse directions.

A still further object of this invention is the provision of an improvedapron conveyor which hasa large loadcarrying capacity, yet is light inweight, and in which apron pans, may be replaced rapidly even inconfined working areas and, in instances while the conveyor itself is inmotion.

These andother objects are accomplished in accordance with the presentinvention by a conveyor having an apron conveyor belt comprised ofaplurality of apron pans in juxtaposed relationship and articulated toeach other by piano hinges. The piano hinges are of like constructionwith each-including a hinge rod positioned between each of thejuxtaposed pans and hinge corrugations at spaced intervals along theopposite sides of each of the apron pans. Thehinge corrugations ofalternate of the juxtaposed apron pans, referred toas suspended pans,pivotally engage with the hinge rods, and are overlapped by thecorrugations of adjacent apron pans, referred to as retainer pans. Lockbars are positioned between the juxtaposed pans and include fingersarranged in interdigitating relationship with the spaced corrugations onsuch pans. At the free ends of each of the fingers is formed a hingecorrugation which opens in a direction opposite to the corrugations ofthe juxtaposed pans and which pivotally engages the hinge rod positionedbetween such pans.

The respective lock bars are secured by removable fasteners to theretainer apron pans and, more particularly, to flanges on such panswhich project in'between and in the same direction as the hingecorrugations .thereof.

that of the respective apron pansand, .in thepreferred embodiment,theindividuallock'barsmay be coextensive with the respectiveseriesof-pans so as to impart greater rigidity. to the conveyorbelt in.its' transverse direction. A stiffener bar, which. extends across theentire width of the conveyorbelt may be releasably attached to thelockbars-at selected or ateach of the piano hinges to-impart stillgreater transverse rigidity to the conveyor belt. I

If necessary forcontaining the conveyor load, side plates may beprovided at the opposite ends of each series-of pans, Preferably thelock bars, or stiffener bars if used, are securedat their ends tocertain. of such side plates by removal fasteners to enhance thetransverse rigidity of the conveyor,.yet permit the limited conveyor.disassembly which is necessary for apron pan replacement. 3

Preferably, the apron conveyor belt is advanced by a pair of laterallyspaced chain link strands whichare supported for movement. along anendless path having a load-carrying run .anda return run, with suitablemeans being provided for driving such strands at a desired rate ofspeed. More'particularly, the'hingerods extend between-the chain strandsand serve as pivot pins for the overlapping links of the respectivestrands. Al-

ternate of the chain links, referred. to hereinas plate links, of eachchain strand may beef-substantial height so as to serveas side-platesfor certain .of the series of apron pans. The remaining of thechainlinks .may .be conventional .bar links to which suitablesideplates maybe attached.

Replacement of a retainer pan is achieved by releasing the.opposite-sides .thereof from the respective lock bars. lf theconveyor.includes stiffener :bars .andside plates, such barsare released .at.least tosuch :an extent 13 to, permit .the same to be moved away fromthe respective adjacent lock bars. These lock :bars may be pivotedaway.from .each other, .if necessary,.afterwhich the worn of .damaged apronpan is removed :and replaced. The lock bars, and stiffener bars .if.used, are then returned to their normal positionand refastened inplace.

When replacing a worn or damaged suspended .pan, the lockbars and, ifpresent, the stiffener barsalong 0pposite sides of such pans .arereleased :as described above. Since .thecorrugations of such suspended.pan are overlappedat oppositesides'thereof by the corrugations of.theadjacent retainer pans, the sides of such adjacent retainer panswhich are remote from the suspended pan which is to be replaced areloosened and preferably released from their respective lock bars. Thislast step facilitates movement of the sides of the retainer pans whichare nearest to the worn or damaged suspended pan and thus permitsremoval and replacement of such suspended pan. Once pan replacement iscompleted, the different lock and stiffener bars are returned to theirnormal positions and resecured.

THe apron pans and lock bars are formed of materials of substantiallylike thickness. Except where extremely heavy loads are to be encounteredthe apron pans and lock bars may be fabricated from light gauge metalsheets, as by stamping followed by corrguating with suitably shapeddies.

The apron conveyor of the present invention is adapted for used in avariety of applications and with different materials. In view of thesnug, yet compact piano hinges, the conveyor described may be employedwith granular or fine materials, and is eminently suited for operationunder high temperature conditions, as for example in the manufacture ofcoke products.

In the drawing, FIG. 1 is a diagrammatic'side view of the apron conveyorof the present invention;

FIG. 2 is a plan view of a portion of the conveyor shown in FIG. 1;

FIG. 3 is a vertical section taken generally along the line [11- III ofFIG. 1; and

FIG. 4 is an expanded perspective view of a hinge of the conveyor of thepresent invention.

With reference to the drawing, the conveyor of the present inventionillustrated is indicated by the character 11 and includes a beltcomprised of a plurality of apron pans in juxtaposed relationship andarticulated to each other by piano hinges indicated at 13. The pianohinges 13 are of like construction, with each including a hinge or crossrod l5, which is positioned between adjacent juxtaposed apron pans 17and 19 and extends across the entire width of the apron belt, and hingecorrugations or curled beads 21 and 23 at spaced intervals along theopposite sides of respective apron pans.

More particularly, the apron pans 17 and 19 include load-carryingsurfaces 25 and 27 which, in the embodiment illustrated, are flat orplanar and are formed with staggered rows of equally spaced perforations29. The

spaced hinge corrugations 21 provided along the op-- posite sides of theapron pans 17 project beyond the load-carrying surfaces 25 thereof theengage directly with the hinge rods 15. The inside surfaces 31 of thecorrugations 21 mate with the peripheries of the hinge rods so as topermit free articulation of the pans 17 relative to such hinge rods.Each of such arcuate surfaces 31 extend through an angle which isgreater than 90and preferably no greater than l80to insure adequatesupport of the pans 17, yet enable such pans to be easily assembled ontoand removed from the hinge rods 15 when it is so desired.

The corrugations 23 provided along the opposite sides of the apron pans19 also project from the loadcarrying surfaces 27 thereof and aresubstantially of the same length and spacing as the corrugations 21 ofthe apron pans 17. While the apron pans 17 are suspended betweenadjacent hinge rods 15, the corrugations 23 of the pans 19 engage overthe corrugations 21 of the parts 17 and serve to retain the suspendedpans 17 in place. Thus, the inside arcuate surfaces 33 of thecorrugation than Ito insure proper support of the pans l9 and facilitateeasy installation and removal thereof.

In addition to the above difference, the apron pans 19 are distinguishedfrom the pans 17 by the presence of flanges37 which project from theirload-carrying surfaces 27 and extend inbetween the'corrugations 23thereof. The flanges 37 along the respective opposite sides of the apronpans 19 are secured by removable fasteners, indicated at 39, toindividual lock bars 41. The lock bars 41 are of like construction, witheach including a continuous web 43 having a length substantially equalto that of the apron pans, and spaced fingers 45 which project from suchweb 43 and are arranged in interdigitating relationship with the pancorrugat ions. At their free ends the lock bar fingers 45 are eachformed with hinge corrugation or curled bead 47 which project from suchweb opens in a direction direction opposite to the corrugations of thejuxtaposed pans 17 and 19, and which mates and pivotally engages withthe hinge rod 15 positioned between such juxtaposed pans.

The piano hinges 13 of the conveyor belt are'compact so that apron pansthemselves have a large loadcarrying capacity. Also, these piano hingesare rather snug, thus minimizing leakage, as when granular materials arebeing transported, yet are open sufficiently to insure proper dischargeof materials therefrom and to permit circuitous passage of gasestherethrough. Of still further significance is that expansionexperienced by the different elements of the piano hinges 13 as forexample during high temperature operating conditions, do not inhibit thefree articulating movement of the apron-pans or look bars, nor involveanysacrifice in the integrity of such hinges.

As shown in FIG. 2 in lieu of having each of the individual apron pans17 and 19 span across the entire width of the conveyor belt, a series ofsuch pans may be pivotally supported between each pair of adjacent hingerods 15, with the pans of each respective series being of likeconstruction.

The webs 43 of the respective lock bars 41 may have a lengthsubstantially equal to that of the individual pans or may extend acrossthe entire width of the conveyor belt. Added transverse rigidity may beand preferably is provided to the conveyor belt by attaching a stiffenerbar 49, which extends across the entire width of the conveyor belt, tothe lock bar webs 43, as by the removable fasteners 39. The stiffenerbars 49 are substantially thicker than the lock bar webs 43 and areangled at their free ends to insure proper discharge of materials fromthe conveyor belt and to enhance the rigidity thereof.

In the specific embodiment illustrated, the conveyor belt is advanced bya pair of like, laterally spaced endless chain link strands 51 which aresupported by shafts 53, 55, 57, and 59 and engaged by sprockets 61carried thereon. More specifically, the hinge rods 15 extend between therespective chain strands 51 and serve as pivot pins for overlappingchain links 63 and 65 and flanged, bushed rollers 67 which are retainedthereon as by cotter pins 69.

The alternate chain links 63 of the innermost series of links of therespective chain strands 51 are hereafter referred to as plate links,while the remaining links of such strands 51 are conventional bar links.The plate links 63 are of a height substantially greater than that ofthe links 65 which are adjacent thereto and serve as side plates for therespective series of apron pans 17. By means of fasteners 71 and fillerbars 73, plates 75 are fixed to the links 65 which are adjacent to theplate links 63 and serve as side plates for the respective series ofapron pans 19. As illustrated in FIG. 3, the substantial overlap existsbetween the plate links 63 and plates 75 to ensure proper containment ofthe material within each series of apron pans as they enter and leavethe load-carrying run of the conveyor which extends between the shafts53 and 55.-

For the sake of still greater rigidity clip angles 77 are fixed, as bywelding, to the opposite ends of the stiffener bars 49 and are securedto the side plates 75 by removable fasteners, as indicated at 79.

The conveyor 11 is advanced at a desired rate of speed by a drivingforce applied to one of the shafts 53, 55, 57 and 59 from a suitablevariable speed motor, coupled with a speed reducer, not shown. As in conventional conveyors, fixed rails 81 are provided for supporting theflanged chain strand rollers 67 as the conveyor 1 1 is advanced alongits load-carrying run.

To accommodate for variations in length which the conveyor 11 mayexperience during different operating conditions, as when the conveyoris cooled after operating in a heated atmosphere, the opposite ends ofthe shaft 59 are rotatably supported by hearing blocks 83, which in turnare slidablysupported by stationary guides 85. A separate cable'87 isattached at 89 to the respective bearing blocks 83, laced over pulleys91 and 93 and carries a plurality of weights 95 at its free end. Thus,as the conveyor 11 is heated and increases in length, the weights 95cause the respective bearing blocks 83 to move to the left, as viewed inFIG. 1, along the guides 85. The shaft 59 will, of course, move with thebearing blocks 83 so that the conveyor is main tained taut and withsprockets 61 carried by the shaft 59 engaged at all times with the chainstrands 51. During subsequent cooling of the conveyor 11, as thecontracting forces which are developed therein exceed the forces exertedby the weights 95, the bearing blocks 83 and the shaft 59 carriedthereby move to the right along the guides 85 and thus prevent damage orrupture of the conveyor itself or distortion of its supporting shafts.

In view of the short lengths of the apron pans l7 and 19, as compared tothe width of the conveyor itself, replacement of worn or damaged apronpans is a rather simple operation which can be effected rapidly, even inclip angles then removedgafterwhich such stiffener bars 49 .and the clipangles 77 .attached thereto are pivoted into position as shown in brokenlines in FIG. 3. Desirably, the freed lock bars 41 are pivoted onto theadjacent suspended pans l7. The/pan -1-9whichis to be replaced is thensimply lifted away-After a-new :pan '19 has been positioned,-the lockbars'4l and the stiffener bars 49 are returned to their originalpositions and resecured in place.

Replacement of a worn -or damaged pan 17 of any one series of such pansrequires that, inaddition-to the above-described steps, the series ofpans 19 on either side of the pan 17 which isto be-replaced be releasedfor at least limited movement. More particularly, .the sides of suchseriesof pans 19 which .are remote from the 'worn or damaged pan 17 ;areloosened and preferably released,- in a manner as heretofore described,from the lock bars 4'1 which are adjacent thereto. When this has beenaccomplished, the sides of such pans 19 which are nearestto the pans 17which is to be removed may-be lifted freely so as to permit the desiredpan replacement.

In view of'the transverse rigidity imparted'tothe conveyor 11 by thehinge rods '15, lock bars 41 and-stiffener bars 49, the apron pansthemselves may bemade from light gauge sheet steel 'which, of course,offers great economies in fabrication .as well as conveyor operation. Toprovide for snug and freely articulating piano hinges 13, the apronpansand thelockbars are of like thickness and, for simplicity, .areformed of like materials. The remaining elements of the conveyor belt,as for-exampletheihinge rods 15 and stiffener bars 49, are of simple.design and can be readily formedfrom commercially available materials.

It is to be-understood that changes'and variations juxtaposed pans,hinge corrugationsatspaced intervals confined working areas. For examplewhen'it is desired 7 along-the opposite sides of each of said'panswith-the corrugations of alternate of saidpans pivotally engaging thehinge rods and being overlapped by the corrugations of the pans adjacentthereto, lock bars positioned between juxtaposed pans .and includingfingers arranged ininterdigitating relationship with the spacedcorrugations of such pans, each of said fingers-having a hingecorrugation at its free end opening-in a direction opposite to thecorrugations of said juxtaposed pans and pivotally engaging the hingerod positioned between such pans, and means securing the respective lockbars to said adjacent pans.

2. An apron conveyor belt as defined .in claim 1 wherein a series ofapron pans are pivotally supported between each pair of adjacent hingerods withthe pans of each respective series of pans being of likeconstruction.

3. An apron conveyor belt as defined in. claim .2 further includingstiffener bars located'between atleast certainof said juxtaposed pansand secured to .theJock bars thereat, each of said stiffener barshavinga=length substantially equal to the width of saidconveyor belt.

4. An apron conveyor belt as defined in claim 2 further including sideplates at the opposite ends of each series of pans.

5. Anapron conveyor belt as defined in claim 1 wherein each of saidadjacent pans includes flanges projecting inbetween and in the samedirection as the hinge corrugations thereof, and wherein the respectivelock bars are secured to the flanges of said adjacent pans.

6. An apron conveyor belt as defined in claim 5 wherein a seriesof apronpans are pivotally supported between each pair of adjacent hinge rodswith the pans of each respective series of pans being of likeconstruction, wherein each lock bar is substantially coextensive witheach respective series of pans, and wherein the respective lock bars aresecured to the flanges of said adjacent pans with removable fasteners tofacilitate independent replacement of individual pans from each suchseries of pans.

7. An apron conveyor belt as defined in claim 6 further including arigid stiffener bar extending substantially coextensive with each of therespective lock bars and being fixed thereto by said removablefasteners.

8. An apron conveyor belt as, defined in claim 7 further including sideplates connected to said hinge rods, and removable fasteners securingthe opposite ends of .said stiffener bars to the side plates at theoppositeends of said series of adjacent pans.

9. An apron conveyor comprising a pair of like laterally spaced chainstrands including hinge rods extending between said pair of strands andlinks having overlapping end portions pivotally connected to said hingerods, means supporting said chain strands for movement along an endlesspath having a load-carrying run and a return run, means includingsprockets for driving said chain strands, an apron pan pivotallysupported between each pair of adjacent hinge rods, hinge corrugationsat spaced intervals along the opposite sides of each of said pans withthe corrugations of alternate of said pans pivotally engaging the hingerods and being overlapped by the corrugations of the pans adjacentthereto, lock bars positioned between juxtaposed pans and includingfingers arranged in interdigitating relationship with the spacedcorrugations of such pans, each of said finger shaving a hingecorrugation at the free end opening in a direction opposite to thecorrugations of said juxtaposed pans and pivotally engagingthe hinge rodpositioned between such pans, and means for securing the respective lockbars to said adjacent pans.

10. An apron conveyor as defined in claim 9 wherein a series of apronpans are pivotally supported between each pair of hinge rods with thepans of the respective series'of pans being of like construction.

1 1. An apron conveyor as defined in claim 10 further includingstiffener bars located between at least certain of the series ofjuxtaposed pans and fixed to the lock bars thereat, each of saidstiffener bars having a length substantially equal to that of saidrespective series of pans.

12. An apron conveyor as defined in claim 10 further including sideplates at the opposite ends of each series f f An apron conveyor asdefined in claim 10 wherein said chain strands are roller chains inwhich the innermost over-lapping links thereof consist of bar links andplate links, said plate links being of substantially greater height thansaid bar 15 links and serving as side plates for said alternate pans,and plates each having a configuration corresponding with that of saidchain plates supported from said bar links in overlapping relationshipwith said chain plates and serving as side plates for said adjacentpans.

14.'An apron conveyor as defined in claim 13 including a rigid stiffenerbar located between at least certain of the series of juxtaposed pansand fixed to the lock bars thereat, each of said stiffener bars having alength substantially equal to that of said respective series of pans,clip angles fixed to each of the opposite ends of the respectivestiffener bars, and means for removably securing said clip angles to theside plates of said ad jacent pans.

15. An apron conveyor as defined in claim 13 wherein each of said apronpans includes a flat load carrying surface, and further includingperforations in the load-carrying surfaces of said pans, and whereinsaid means for supporting said chain strands includes fixed rails atleast along the load-carrying run of said chain strands along which ridesaid rollers.

16. An apron conveyor as defined in claim 9 wherein each of said apronpans includes-a load carrying surface, wherein the hinge corrugationsalong the respective pans project beyond the respective load carryingsurfaces thereof, and wherein flanges integral with the respective loadcarrying surfaces project inbetween and in the same direction as thehinge corrugations thereof.

17. An apron conveyor as defined in claim 16 wherein a series of apronpans are pivotally supported between each pair of hinge rods with thepans of the respective series of pans being of like construction,wherein each lock bar is substantially coextensive with the respectiveseries of pans and wherein the respective lock bars are secured to theflanges of said adjacent pans with removable fasteners to facilitateindependent replacement of individual pans from each such series ofpans.

18. An apron conveyor as defined in claim 17 further including a rigidstiffener bar substantially coextensive with each of the respective lockbars and fixed thereto by said removable fasteners.

(u/ss) Patent No Dated September 12, 1972 Inventor(s) Ralph C. Ouska Itis certified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected asshown below:

change "WIth" to ---With-.

after "pans" delete the comma and insert a period;

53, delete "l3" 56, change "of" to as 8, change 'I'He" to --The;

48, change "the" to *---and-- v 24, delete "projectfrom such web" 24,delete "direction" 67, after "stiffener" insert --bars--.

I, delete "clip angles".

46, change "finger shaving" to --fingers having--. 13, delete "15".

Signed and sealed this 20th day of November 1973.

Col. 1, line Col. 2, line Col. 2, line Col. 2, line Col. 3, line Col. 3,line Col. 4, line Col. 4, line Col. 5, line Col. 6, line Col. 7, lineCol'. 8, line .(S L Attest:

snwARn M. FLE'I'CHER,JR. Attestin'g Officer RENE D. TEGTMEYER ActingCommissioner of Patents

1. In a conveyor, an apron conveyor belt comprising a plurality ofconveyor apron pans in juxtaposed relationship, a hinge rod positionedbetween each of the juxtaposed pans, hinge corrugations at spacedintervals along the opposite sides of each of said pans with thecorrugations of alternate of said pans pivotally engaging the hinge rodsand being overlapped by the corrugations of the pans adjacent thereto,lock bars positioned between juxtaposed pans and including fingersarranged in interdigitating relationship with the spaced corrugations ofsuch pans, each of said fingers having a hinge corrugation at its freeend opening in a direction opposite to the corrugations of saidjuxtapOsed pans and pivotally engaging the hinge rod positioned betweensuch pans, and means securing the respective lock bars to said adjacentpans.
 2. An apron conveyor belt as defined in claim 1 wherein a seriesof apron pans are pivotally supported between each pair of adjacenthinge rods with the pans of each respective series of pans being of likeconstruction.
 3. An apron conveyor belt as defined in claim 2 furtherincluding stiffener bars located between at least certain of saidjuxtaposed pans and secured to the lock bars thereat, each of saidstiffener bars having a length substantially equal to the width of saidconveyor belt.
 4. An apron conveyor belt as defined in claim 2 furtherincluding side plates at the opposite ends of each series of pans.
 5. Anapron conveyor belt as defined in claim 1 wherein each of said adjacentpans includes flanges projecting inbetween and in the same direction asthe hinge corrugations thereof, and wherein the respective lock bars aresecured to the flanges of said adjacent pans.
 6. An apron conveyor beltas defined in claim 5 wherein a series of apron pans are pivotallysupported between each pair of adjacent hinge rods with the pans of eachrespective series of pans being of like construction, wherein each lockbar is substantially coextensive with each respective series of pans,and wherein the respective lock bars are secured to the flanges of saidadjacent pans with removable fasteners to facilitate independentreplacement of individual pans from each such series of pans.
 7. Anapron conveyor belt as defined in claim 6 further including a rigidstiffener bar extending substantially coextensive with each of therespective lock bars and being fixed thereto by said removablefasteners.
 8. An apron conveyor belt as defined in claim 7 furtherincluding side plates connected to said hinge rods, and removablefasteners securing the opposite ends of said stiffener bars to the sideplates at the opposite ends of said series of adjacent pans.
 9. An apronconveyor comprising a pair of like laterally spaced chain strandsincluding hinge rods extending between said pair of strands and linkshaving overlapping end portions pivotally connected to said hinge rods,means supporting said chain strands for movement along an endless pathhaving a load-carrying run and a return run, means including sprocketsfor driving said chain strands, an apron pan pivotally supported betweeneach pair of adjacent hinge rods, hinge corrugations at spaced intervalsalong the opposite sides of each of said pans with the corrugations ofalternate of said pans pivotally engaging the hinge rods and beingoverlapped by the corrugations of the pans adjacent thereto, lock barspositioned between juxtaposed pans and including fingers arranged ininterdigitating relationship with the spaced corrugations of such pans,each of said finger shaving a hinge corrugation at the free end openingin a direction opposite to the corrugations of said juxtaposed pans andpivotally engaging the hinge rod positioned between such pans, and meansfor securing the respective lock bars to said adjacent pans.
 10. Anapron conveyor as defined in claim 9 wherein a series of apron pans arepivotally supported between each pair of hinge rods with the pans of therespective series of pans being of like construction.
 11. An apronconveyor as defined in claim 10 further including stiffener bars locatedbetween at least certain of the series of juxtaposed pans and fixed tothe lock bars thereat, each of said stiffener bars having a lengthsubstantially equal to that of said respective series of pans.
 12. Anapron conveyor as defined in claim 10 further including side plates atthe opposite ends of each series of pans.
 13. An apron conveyor asdefined in claim 10 wherein said chain strands are roller chains inwhich the innermost over-lapping links thereof consist of bar links andplate links, said plate links being of substantially greater height thansaid bar 15 links and serving as side plates for said alternate pans,and plates each having a configuration corresponding with that of saidchain plates supported from said bar links in overlapping relationshipwith said chain plates and serving as side plates for said adjacentpans.
 14. An apron conveyor as defined in claim 13 including a rigidstiffener bar located between at least certain of the series ofjuxtaposed pans and fixed to the lock bars thereat, each of saidstiffener bars having a length substantially equal to that of saidrespective series of pans, clip angles fixed to each of the oppositeends of the respective stiffener bars, and means for removably securingsaid clip angles to the side plates of said adjacent pans.
 15. An apronconveyor as defined in claim 13 wherein each of said apron pans includesa flat load carrying surface, and further including perforations in theload-carrying surfaces of said pans, and wherein said means forsupporting said chain strands includes fixed rails at least along theload-carrying run of said chain strands along which ride said rollers.16. An apron conveyor as defined in claim 9 wherein each of said apronpans includes a load carrying surface, wherein the hinge corrugationsalong the respective pans project beyond the respective load carryingsurfaces thereof, and wherein flanges integral with the respective loadcarrying surfaces project inbetween and in the same direction as thehinge corrugations thereof.
 17. An apron conveyor as defined in claim 16wherein a series of apron pans are pivotally supported between each pairof hinge rods with the pans of the respective series of pans being oflike construction, wherein each lock bar is substantially coextensivewith the respective series of pans and wherein the respective lock barsare secured to the flanges of said adjacent pans with removablefasteners to facilitate independent replacement of individual pans fromeach such series of pans.
 18. An apron conveyor as defined in claim 17further including a rigid stiffener bar substantially coextensive witheach of the respective lock bars and fixed thereto by said removablefasteners.